FALMOUTH, Jamaica — Tourists emerge by the hundreds from a towering, 16-deck megaship docked at the Caribbean’s newest cruise port. They squint in the glare of the Jamaican sun, peer curiously at a gaggle of locals beyond a wrought-iron fence, and then roar out of town on a procession of air-conditioned tour buses.

Few stop to buy T-shirts, wooden figurines, or beach towels from the dozens of merchants lining the road outside the fence, or visit the colonial-era buildings that dot the town. Not many even venture beyond the terminal’s gates, unless it’s in one of the buses that whisk them past increasingly disgruntled vendors and taxi drivers.

That’s not the way townspeople in the old Jamaican ­sugar port of Falmouth were told it would be.

Jamaica’s port authority and Royal Caribbean Cruises Ltd. pitched the $220 million port as a place where passengers would dive into the historic city for ‘‘a wraparound experience not unlike Colonial Williamsburg, but one that is infused with the signature warmth of the Jamaican people.’’ Locals were told the tourists might spend more than $100 each.

But since the industry’s biggest ships started arriving early last year that warmth and those dollars have been kept at a distance.

‘‘We were promised that we’d be able to show people our Jamaican heritage, sell our crafts. But most of the tourists stay far away from the local people,’’ said Asburga Harwood, an independent tour guide and community historian. ‘‘We’re on the losing end.’’

Trade groups say the flourishing cruise ship industry injects about $2 billion a year into the economies of the Carib-bean, the world’s number one cruise destination. But critics complain it produces relatively little local revenue because so many passengers dine, shop, and purchase heavily marked-up shore excursions on the boats or splurge at international chain shops on the piers.

The World Bank said in a 2011 report on Jamaica that as much as 80 percent of tourism earnings do not stay in the ­Caribbean region, one of the highest ‘‘leakage’’ rates in the world.

‘‘In all-inclusive Caribbean hotels it is common for only 20 percent of revenue to be returned to the local economy. In the case of cruise ships it will be much less, probably no more than 5 percent,’’ said Victor Bulmer-Thomas, a professor emeritus at London University who is a specialist on Caribbean and Latin America economies.

A new report commissioned by the Florida-Caribbean Cruise Association trade group says passengers spent $1.48 billion during port calls in the 2011-12 season at 21 destinations.

But $583 million of that money went for watches and jewelry bought in cruise destinations where international chains like Colombian Emeralds and Diamonds International dominate pier shopping. An additional $270 million went to shore excursions, which are typically sold by the cruise lines. Just $87 million went to local crafts and souvenirs, according to the report.

The criticism isn’t confined to Jamaica. Some Caribbean ports are even designed to prevent interaction with the surrounding communities.

In Haiti, the Western Hemisphere’s poorest nation, tourists step off Royal Caribbean ships to visit the fenced-in beach attraction Labadee on the country’s north coast. The visitors are prohibited from leaving the cruise line’s property, which features white-sand beaches and one of the longest zip lines in the world.

‘‘They should allow tourists to venture to the city. This would help the local economy,’’ said Jean Cherenfant, mayor of nearby Cap-Haitien. ‘‘The majority of the people (in Cap-Haitien) don’t feel the presence of Royal Caribbean and the tourists.’’

But each passenger to ­Labadee pays a $10 tax to the Haitian government, producing more than $6 million a year for the impoverished nation.

In the Bahamas, Disney Cruise Line ships stop at the company’s private island, dubbed Castaway Cay, where locals work as massage therapists, bartenders, and drivers and supplies are brought in by the ships.

John Issa, former head of ­Jamaica’s hotel association, said the cruise lines enjoy an unfair advantage over land-based businesses because regional governments fear the ships may pull out for a competing destination, while ‘‘once you put down a hotel, you are captive.’’

In one famous case, Carnival Cruise Lines withdrew from Grenada in 1999 amid a dispute over a $1.50-a-head tax to pay for a new landfill.

‘‘The governments are terrified of making more demands,’’ Bulmer-Thomas said.

The cruise industry says the ships steadily bring in huge amounts of tourists who otherwise might never come at all, so any money they do spend is a gain.

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